WO2020187287A1

WO2020187287A1 - Optical anti-counterfeiting element and optical anti-counterfeiting product

Info

Publication number: WO2020187287A1
Application number: PCT/CN2020/080181
Authority: WO
Inventors: 张宝利; 胡春华; 王晓利; 朱军
Original assignee: 中钞特种防伪科技有限公司; 中国印钞造币总公司
Priority date: 2019-03-19
Filing date: 2020-03-19
Publication date: 2020-09-24
Also published as: CN111716936B; CN111716936A

Abstract

Provided are an optical anti-counterfeiting element and an optical anti-counterfeiting product including same. The optical anti-counterfeiting element (1) comprises: a base layer (101); a colour function layer (103) located on the base layer; a first micro-relief structure (102) covering at least a portion of a first area (B) of the colour function layer, the first area being a partial area of the colour function layer; a plating layer (104) only covering the surface of the first micro-relief structure. The first micro-relief structure is defined such that when a light beam irradiates the first micro-relief structure at an incident angle, light of a wavelength or wavelength range in the light beam interferes constructively on a reflection direction. In addition, the colour function layer and the first micro-relief structure can provide optical characteristics having different colour characteristics. The optical anti-counterfeiting element has the advantages of being highly reliable, easy to identify, and difficult to forge.

Description

Optical anti-counterfeiting components and optical anti-counterfeiting products

Technical field

The invention relates to the field of optical anti-counterfeiting, in particular to an optical anti-counterfeiting element and an optical anti-counterfeiting product.

Background technique

In order to prevent counterfeiting by means of scanning and copying, anti-counterfeiting technologies for diffractive optically variable images (such as holograms, dynamic diffraction patterns, etc.) are widely used in various high-security or high-value-added printed materials such as banknotes, cards, and product packaging. And achieved very good results. For example, large denomination Euro banknotes use diffractive light variable image hot stamping logos, small denominations use diffractive light variable image hot stamping wide strips, and China 2005 version of Renminbi uses diffractive light variable image window security lines except for one yuan side. Visa, MasterCard and China UnionPay credit cards use diffractive light-varying image hot stamping logos, and important documents such as Chinese ID cards, driving licenses, and passports also use diffractive light-varying image anti-counterfeiting technology. So far, most of the world's banknotes, credit cards, passports and other security cards have adopted diffractive light variable image anti-counterfeiting technology.

The diffractive optically variable image used for anti-counterfeiting is a grating with a relief structure. When the illuminating light (such as natural light) is irradiated on its surface, diffraction occurs, and the reproduced image is formed by using its 1st (or -1) diffracted light to achieve Public anti-counterfeiting features such as eye-catching dynamics, three-dimensionality, and color changes.

With the increasing popularity of diffractive optically variable image technology, this technology has also been widely used in general commodities and packaging, such as the packaging of cigarettes, wine, medicines, etc., and even the labels of textiles and toys. This kind of anti-counterfeiting technology is becoming easier to implement, which greatly reduces the anti-counterfeiting performance of this technology. Therefore, a new and more reliable anti-counterfeiting technology is needed.

Chinese patent application CN104249597A discloses an optical anti-counterfeiting element, the microstructure contained in it is defined as when a light beam is irradiated at an angle of incidence, light of a wavelength or wavelength range in the light beam interferes in the direction of transmitted light or reflected light Constructive. The optical anti-counterfeiting element is different from the above-mentioned diffracted light-changing image, avoiding the interference of diffracted light with the rainbow characteristic of uncertain colors, but using the easy-to-describe color stable light formed by the interference mechanism, so that the optical anti-counterfeiting element The area covered by the micro-relief structure forms a specific pattern that is easy to identify and difficult to forge. However, as banknotes, ID documents and other products have an increasing demand for high anti-counterfeiting technology, the optical anti-counterfeiting element needs to be further improved. Attributes that are easy to identify and difficult to forge.

In order to prevent counterfeiting of various types of high-security or high-value-added printed materials such as banknotes, certificates and product packaging, multi-layer structure coating technology is widely used. Multi-layer structure coating technology can present various color characteristics or different colors under different viewing angles, and cannot be imitated or copied by electronic equipment such as cameras, scanners, printers, etc., so it has a high anti-counterfeiting ability. However, simply using multi-layer coating technology can no longer meet the needs of the anti-counterfeiting field.

Combining the multi-layer structured coating with the anti-counterfeiting element disclosed in Chinese patent application CN104249597A can bring rich and unique optical anti-counterfeiting features. However, since both of them will selectively constructively interfere with the incident light wavelength, this combination will produce Contradiction, the color provided by the multi-layer structure coating or the color feature provided by the anti-counterfeiting element disclosed in Chinese patent application CN104249597A are significantly weakened, which is not conducive to the identification of anti-counterfeiting features. Therefore, it is necessary to further develop a new type of optical anti-counterfeiting element.

Summary of the invention

The purpose of the embodiments of the present invention is to provide an optical anti-counterfeiting element and an optical anti-counterfeiting product that are more reliable and easy to identify and difficult to forge.

In order to achieve the above object, the present invention provides an optical anti-counterfeiting element, the optical anti-counterfeiting element comprising: a base layer; a color functional layer located on the base layer; a first micro-relief covering at least a part of a first area of the color functional layer Structure, the first area is a partial area of the color functional layer; and the plating layer only covers the surface of the first micro-relief structure; the first micro-relief structure is defined as when the light beam is irradiated at an incident angle In the first micro-relief structure, light of a wavelength or wavelength range in the light beam interferes constructively in the direction of the reflected light.

Correspondingly, the present invention also provides an optical anti-counterfeiting product, including the above-mentioned optical anti-counterfeiting element.

Through the above technical solution, it is possible to realize an optical anti-counterfeiting feature that is not only clearly different from the diffractive optically variable image anti-counterfeiting technology, but also different from the simple multilayer structure coating. The sample containing this feature provides different observations in the first micro-relief structure area. The angles respectively present two complementary color features, while the remaining areas provide the color features of the color function layer. The sharp contrast and contrast can be achieved by separately defining the structural parameters of the first micro-relief structure and the color functional layer, and a unique optical anti-counterfeiting element with easy identification and difficult to forge characteristics can be formed.

Other features and advantages of the embodiments of the present invention will be described in detail in the following specific implementation section.

Description of the drawings

The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the attached picture:

Figures 1a to 1b show an optical security element according to an embodiment of the present invention;

1c to 1d show schematic diagrams of the cross-sectional shape of the relief unit of the micro-relief structure;

Figures 2a to 2b show an optical security element according to an embodiment of the present invention;

3a to 3c show an optical security element according to an embodiment of the present invention;

4a to 4f show schematic diagrams of the manufacturing process of an optical anti-counterfeiting element according to an embodiment of the present invention;

5a to 5c show schematic top views of an optical security element according to an embodiment of the present invention;

6a to 6b show schematic top views of an optical anti-counterfeiting element according to an embodiment of the present invention;

Figure 7 shows a schematic cross-sectional view of an optical security element according to an embodiment of the present invention; and

Fig. 8 shows a schematic cross-sectional view of an anti-counterfeiting element according to an embodiment of the present invention.

detailed description

The specific implementation manners of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific implementations described here are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

The "feature size" mentioned in the present invention refers to the average value of the lowest and highest surface heights in the micro-relief structure to divide the surface to form the size of the contour surrounding the convex or concave part in any direction.

"Micro-relief structure" refers to the uneven microstructure formed on a two-dimensional surface as needed.

The "relief unit" refers to a single convex or concave part formed by dividing the surface into a single convex or concave part in the micro-relief structure by taking the average of the lowest and highest points on the surface of the micro-relief structure, and its characteristic size is on the order of microns. The "depth d of the micro-relief structure" refers to the height difference between the highest point and the lowest point of the surface height in the micro-relief structure.

Fig. 1a shows an optical security element 1 according to an embodiment of the present invention. 1a is a schematic cross-sectional view of an anti-counterfeiting element 1 according to an embodiment of the present invention. The optical anti-counterfeiting element 1 includes a base layer 101, a color function layer 103 on the base layer 101, and an area B on the color function layer 103 and covering the color function layer 103 At least a part of the micro-relief structure 102, and the plating layer 104 only covering the micro-relief structure 102. The area B is a partial area of the area of the color functional layer 103, and the area of the color functional layer 103 except for the area B is called area A. The micro-relief structure 102 is defined as when a light beam illuminates the micro-relief structure 102 at an incident angle, light of a wavelength or wavelength range in the beam interferes constructively in the direction of the reflected light, and the color functional layer 103 and the micro-relief structure 102 can provide optical features with different color features.

Preferably, the color functional layer 103 may be an interference type multilayer film structure, which forms a Fabry-Perot resonant cavity, which has a selective effect on the incident white light, so that the emitted light only contains certain These wavelengths present a specific color; when the incident angle changes, the relative optical path changes, and the interference waveband also changes, so that the color presented to the observer in the direction of the exit angle also changes, thereby forming a light change effect. The interference-type multilayer film structure may include any one of the following structures: (1) A plating layer formed by stacking an absorption layer, a low refractive index medium layer, and a reflective layer in sequence, wherein the reflective layer is the same as the surface of the base layer 101. Contact; (2) a coating layer formed by stacking a high refractive index medium layer, a low refractive index medium layer, and a high refractive index medium layer in sequence; and (3) a coating layer formed by stacking an absorption layer, a high refractive index medium layer, and a reflective layer in sequence , Wherein the reflective layer is in contact with the surface of the base layer 101. Preferably, the material of the above-mentioned reflective layer can be a material with high reflectivity, such as gold, silver, copper, aluminum, zinc, nickel, titanium, etc. and their alloys; the material requirement of the above-mentioned absorbing layer is that its refractive index and Materials with close absorption coefficients, for example, can be semi-metallic materials (such as silicon, germanium, etc.), or metal materials or their alloys (such as chromium, copper, nickel, nickel-chromium alloys, etc.); the aforementioned low refractive index dielectric layer The refractive index is less than 1.7, such as magnesium fluoride, silicon dioxide, cryolite, etc.; the refractive index of the above-mentioned high refractive index dielectric layer is greater than or equal to 1.7, such as ZnS, TiN, TiO ₂ , TiO, Ti ₂ O _3. Ti ₃ O ₅ , Ta ₂ O ₅ , Nb ₂ O ₅ , CeO ₂ , Bi ₂ O ₃ , Cr ₂ O ₃ , Fe ₂ O ₃ , HfO ₂ , ZnO, etc. The interference type multilayer film structure can be obtained by physical or chemical vapor deposition methods such as thermal evaporation, electron beam evaporation, and magnetron sputtering.

Preferably, the color functional layer 103 may be an absorbing structure, where the absorbing structure may be one or a combination of ink, pigment, and dye. Further preferably, the OVI optically variable ink produced by Sicpa can be used, for example.

Preferably, the color functional layer 103 may also be a liquid crystal light variable layer. Typically, for example, a cholesteric liquid crystal material can be used to realize the color function layer 103, so that color characteristics such as green to blue, red to green, etc., which are changed with the observation angle, can be realized. The liquid crystal light variable layer can be mass-produced by coating, printing and other methods.

Preferably, the color functional layer 103 can also be a multi-layer co-extruded optically variable film. Moreover, the multi-layer co-extruded optical variable film can be directly used as the base layer 101.

In order to facilitate the description of the micro-relief structure 102, an x-y-z spatial coordinate system is defined. As shown in Fig. 1b, the micro-relief structure 102 may be located on the xoy plane (or a plane parallel to the xoy plane), and the feature size in the x-axis and y-axis directions may be, for example, 0.3 μm-6 μm, preferably 0.6 μm-3 μm, And the pattern of the micro-relief structure 102 (ie, the relief units of the micro-relief structure) may be randomly or pseudo-randomly distributed. The raised portion of the micro-relief structure 102 may account for 20%-80% of the total area of the micro-relief structure 102, preferably 35%-65%. As shown in FIG. 1a, the cross-sectional shape of the relief unit of the micro-relief structure 102 may be sinusoidal. As shown in FIG. 1c, the cross-sectional shape of the relief unit of the micro-relief structure 102 may be sawtooth. As shown in FIG. 1d, the cross-sectional shape of the relief unit of the micro-relief structure 102 may be a rectangle. Those skilled in the art can understand that the cross-sectional shape of the relief unit of the micro-relief structure 102 may also be other shapes. The depth d of the micro-relief structure 102 can meet the following conditions, that is, when natural light (white light) illuminates the micro-relief structure 102 at an incident angle α, after the light beam passes through the micro-relief structure 102, light with a wavelength of λ or a wavelength range is in the reflected light direction The upper interference is constructive, so that when the optical security element 1 is viewed in the direction of reflected light, it presents a first color, and when the optical security element 1 is viewed in the direction of scattered light, it presents a second color (as shown in Fig. 1a).

The depth d of the micro-relief structure 102 is usually between 100 nm and 5 μm, preferably 200 nm to 3 μm. The depth d can be determined by the following method.

① shows the complex amplitude transmittance τ _{g of the} micro-relief structure 102, τ _g is a function of the depth d, the design wavelength λ, the groove type of the micro-relief structure 102, the material refractive index distribution n, and the position (x, y); ② Perform Fourier transform on the complex amplitude transmittance τ _g ; ③ find the maximum condition of the reflected light with wavelength λ (ie zero-order diffracted light); ④ calculate the depth d of the micro-relief structure 102 according to the maximum reflected light condition.

For example, when the design wavelength λ=600nm, the refractive index of the material of the micro-relief structure 102 is n=1.5, the cross-sectional shape of the micro-relief structure 102 is sinusoidal, and the external medium is air, when d=1528.8nm, the anti-counterfeiting element 1 is reflecting It appears red in the light direction and blue-green in the scattered light direction. If d=2668.8nm, since light with a wavelength of 410.8nm also satisfies the constructive condition of reflected light interference, the anti-counterfeiting element 1 presents magenta in the direction of reflected light and green in the direction of scattered light.

The micro-relief structure can be made into a master by laser etching, electron beam etching, ion etching, etc., and then copied onto the base layer by processes such as electroforming, molding, and UV replication. A more commonly used process is to coat an imaging layer on the surface of the base layer, and copy the micro-relief structure on the imaging layer, with the purpose of improving the quality and efficiency of copying the micro-relief structure.

The material constituting the micro-relief structure can be, for example, ZnS, ZnO, Ta ₂ O ₅ , SnO ₂ , Nb ₂ O ₅ , HfO ₂ , In ₂ O ₃ , CeO ₂ , Dy ₂ O ₃ , Bi ₂ O ₃ , MgF ₂ , Al ₂ O ₃ , AlF ₃ , CaF ₂ , SiO ₂ , SrF ₂ , YbF ₃ , NaF, Na ₃ AlF ₆ , PET, PVC, PE, polyester glue, or polyurethane glue, etc.

The base layer can be, for example, a transparent material such as PET, PVC, or PE, or a carrier such as paper, printed matter, and packaging. The substrate may also be a carrier in the processing process, and be peeled off during later application.

In this embodiment, the plating layer 104 may be, for example, a metal reflective layer. Preferably, the material constituting the metal reflective layer may include, for example, gold, silver, copper, iron, tin, nickel, chromium, aluminum, zinc, titanium and alloys thereof, and the thickness may be greater than 5 nm, preferably greater than 10 nm. The coating layer 104 can be obtained by physical or chemical vapor deposition methods such as thermal evaporation, electron beam evaporation, magnetron sputtering, and the like. The function of the plating layer 104 is to provide a reflection function for the micro-relief structure 102, thereby enhancing the efficiency of reflected light. When the plating layer 104 has a color characteristic, the effect is the superposition of the color characteristic and the color characteristic provided by the micro-relief structure 102.

The optical anti-counterfeiting features of the respective parts of the area A and the area B in the optical anti-counterfeiting element 1 shown in FIGS. 1a to 1b will be described below.

In general, the optical characteristics of the area A in the optical anti-counterfeiting element 1 depend on the choice of the color functional layer 103 in the above preferred solutions. There are two possibilities. One is to provide a single color that is constant at various viewing angles. , The other is to provide the feature that the color changes when the viewing angle changes. Regardless of the choice, assuming that only the color functional layer 103 provides the anti-counterfeiting features of the optical anti-counterfeiting element, its anti-counterfeiting effect is single and not prominent, and the anti-counterfeiting features provided by the part where area B is located provide a powerful supplement to this: First, The part where area B is located can provide color changes and complementary color characteristics in the direction of reflected light and scattered light, which is not available in the color functional layer 103 of the part where area A is located; second, the color characteristics of the part where area B is located depends on Because of the micro-relief structure 102's morphology, refractive index n, its parameter distribution on the xoy plane, and the structure depth d, the color or color provided by the part where the area B is located and the part where the area A is located can be changed by calculation and design parameters. The characteristics are different, and even strong contrast and contrast are formed, so that the optical anti-counterfeiting element of the present invention has stronger uniqueness, and achieves the purpose of being more easily recognized by the public and difficult for counterfeiters to forge.

In practical applications, for example, the following preferred solutions can be used to configure the part where the area A is located and the part where the area B is located:

(1) The first configuration

Color functional layer: select the color functional layer 103 as red nano ink.

Micro-relief structure: the refractive index of the material of the micro-relief structure 102 is n=1.50, the cross-sectional shape of the micro-relief structure 102 is sinusoidal, and the external medium is air, then d=1528.8nm, so the area where the micro-relief structure 102 in the anti-counterfeiting element 1 is located is It appears red in the direction of reflected light and blue-green in the direction of scattered light.

Optical anti-counterfeiting features: when viewed in the direction of reflected light, the part where area A is located and the part where area B is located tend to be red; when viewed in the direction of scattered light, the part where area A is located is red, and the part where area B is located is blue-green.

(2) The second configuration

Color function layer: select the color function layer 103 as green metallic ink.

Micro-relief structure: the refractive index of the material of the micro-relief structure 102 is n=1.50, the cross-sectional shape of the micro-relief structure 102 is sinusoidal, and the external medium is air, then d=2668.8nm, so the area where the micro-relief structure 102 in the anti-counterfeiting element 1 is located is It appears magenta in the direction of reflected light, and green in the direction of scattered light.

Optical anti-counterfeiting features: when viewed in the direction of reflected light, the part where area A is located is metallic green, and the part where area B is located tends to red; when viewed in the direction of scattered light, the part where area A and area B are located both tend to green .

(3) The third configuration

Color functional layer: Select the color functional layer 103 to be OVI ink produced by Sicpa Company. The OVI ink is green when viewed along the z-axis, and blue when viewed at an angle of 45° to the z-axis.

Micro-relief structure: the refractive index of the micro-relief structure 102 material is n=1.48, the cross-sectional shape of the micro-relief structure 102 is rectangular, and the external medium is air, then d=600nm, so the area where the micro-relief structure 102 in the anti-counterfeiting element 1 is reflecting light It appears green in the direction and magenta in the direction of scattered light.

Optical anti-counterfeiting features: when viewed in the direction of reflected light, both the area where the area A is located and the area where the area B is located tend to be green; during oblique observation, the area where the area A is located turns green, and the portion where the area B located turns to magenta.

(4) The fourth configuration

Color functional layer: Select the color functional layer 103 as an interference type multilayer film structure that sequentially contains Al (thickness: 40nm)/SiO2 (thickness: 370nm)/Cr (thickness: 5nm), which is an interference-type multilayer structure of this parameter The film is golden yellow when viewed from the front and green when viewed obliquely.

Optical anti-counterfeiting features: when viewed in the reflected light direction, the part where area A is located is golden yellow, and the part where area B is located are all green; during oblique observation, the part where area A is located turns green, and the part where area B turns to magenta .

(5) The fifth configuration

Color functional layer: The color functional layer 103 is selected to be a cholesteric liquid crystal light variable film produced by Rolic, Switzerland, which adopts red-green characteristics, that is, red when viewed from the front and green when viewed obliquely.

Micro-relief structure: the refractive index of the material of the micro-relief structure 102 is n=1.48, the cross-sectional shape of the micro-relief structure 102 is sinusoidal, and the external medium is air, then d=500nm, so the area where the micro-relief structure 102 in the anti-counterfeiting element 1 is reflecting It appears yellow in the direction of light and blue in the direction of scattered light.

Optical anti-counterfeiting features: when viewed in the direction of reflected light, the area where the area A is located is red, and the area where the area B is located is yellow; during oblique observation, the area where the area A is located turns green, and the portion where the area B located turns blue.

(6) The sixth configuration

Color functional layer: The color functional layer 103 is selected as a multi-layer co-extruded optically variable film produced by 3M Company, which adopts a green-blue characteristic, that is, green when viewed from the front and blue when viewed obliquely.

Optical anti-counterfeiting features: the part where area A is observed in the reflected light direction is green, and the part where area B is yellow; during oblique observation, the part where area A is located and the part where area B is located tend to blue.

The above is an embodiment in which the color functional layer 103 and the micro-relief structure are configured so that the part where the area A is located and the part where the area B is located have different colors or color change characteristics. It should be noted that although there is a situation where the color of the part where the area A is located and the part where the area B is located are the same at a specific observation angle, objectively, there are still differences in the absorption or reflection spectra of the two in practice, but this is essentially The above does not affect the anti-counterfeiting performance and quality of the optical anti-counterfeiting element 1 of the present invention, and the difference can help attract and help users to recognize the pattern of the part where the area A is located or the part where the area B is located.

Figures 2a and 2b show a reflective optical security element 2 according to an embodiment of the present invention. As shown in the figure, an optical anti-counterfeiting element 2 is provided, including a base layer 201, a color functional layer 203 on the base layer 201, a micro-relief on the color functional layer 203 and covering at least a part of the area B of the color functional layer 203 The structure 202, and the plating layer 204 only covering the micro-relief structure 202. The area B is a partial area of the area of the color functional layer 203, and the area of the color functional layer 203 except for the area B is called area A. The micro-relief structure 202 is defined as when a light beam illuminates the micro-relief structure 202 at an incident angle, light of a wavelength or wavelength range in the light beam interferes constructively in the direction of the reflected light, and the color functional layer 203 and the micro-relief structure 202 can provide optical features with different color features.

For ease of description, define the x-y-z spatial coordinate system. As shown in Figure 2a, the micro-relief structure 202 can be located on the xoy plane (or a plane parallel to the xoy plane), and the feature size in the x-axis direction can be greater than 6 μm, preferably greater than 10 μm, so that the micro-relief structure 202 is in this direction Without diffraction effect, the feature size of the micro-relief structure 202 in the y-axis direction may be 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the pattern may be randomly or pseudo-randomly distributed. The protruding portion of the micro-relief structure 202 may occupy 20%-80% of the total area of the micro-relief structure 202, preferably 35%-65%. Figure 2b is a schematic cross-sectional view of an anti-counterfeiting element in a Yoz plane (or a plane parallel to the Yoz plane) according to an embodiment of the present invention. As shown in FIG. 2b, the cross-sectional shape of the relief unit of the micro-relief structure 202 may be sinusoidal. However, those skilled in the art can understand that the cross-sectional shape of the relief unit of the micro-relief structure 202 may be sawtooth, rectangular or other shapes. The depth d of the micro-relief structure 202 can meet the following conditions, that is, when natural light (white light) illuminates the micro-relief structure 202 at an incident angle α, after the light beam passes through the micro-relief structure 202, light with a wavelength of λ or a wavelength range is in the reflected light direction The upper interference is constructive, so that the optical anti-counterfeiting element 2 presents the first color in the direction of the reflected light. In addition, if the light beam is in the Yoz plane (or a plane parallel to the Yoz plane), the optical anti-counterfeiting element 2 presents a second color in the direction of the scattered light in the Yoz plane (or a plane parallel to the Yoz plane).

The depth d of the micro-relief structure 202 may be 100 nm-5 μm, preferably 200 nm-3 μm. The method for determining the depth d is the same as the foregoing embodiment, and will not be repeated here. In addition, other features and beneficial effects of the optical anti-counterfeiting element 2 are the same as those of the above-mentioned optical anti-counterfeiting element 1, and will not be repeated here.

Figures 3a-3c show a reflective optical security element 3 according to an embodiment of the present invention. As shown in the figure, an optical anti-counterfeiting element 3 is provided, including a base layer 301, a color functional layer 303 located on the base layer 301, a micro-relief on the color functional layer 303 and covering at least a part of the area B of the color functional layer 303 The structure 302, and the plating layer 304 only covering the microstructure. The area B is a partial area of the area of the color functional layer 303, and the area of the color functional layer 303 except for the area B is called area A. The micro-relief structure 302 is defined as when a light beam illuminates the micro-relief structure 302 at an incident angle, light of a wavelength or wavelength range in the light beam interferes constructively in the direction of the reflected light, and the color functional layer 303 and the micro-relief structure 302 can provide optical features with different color features.

For ease of description, define the x-y-z spatial coordinate system. As shown in Figure 3a, the micro-relief structure 302 can be located on the xoy plane (or a plane parallel to the xoy plane), the feature size in the y-axis direction can be, for example, 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the pattern can be Randomly or pseudo-randomly distributed, the feature size in the x-axis direction may be 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the pattern may be, for example, a periodic structure. The protruding part of the micro-relief structure 302 may occupy 20%-80% of the total area of the micro-relief structure 302, preferably 35%-65%. Figure 3b is a schematic cross-sectional view of the anti-counterfeiting element 3 in the Yoz plane (or a plane parallel to the Yoz plane) according to an embodiment of the present invention, and Figure 3c is the anti-counterfeiting element 3 in accordance with an embodiment of the present invention in the xoz plane (or with xoz plane parallel plane) cross-sectional schematic diagram. The cross-sectional shape of the relief unit of the micro-relief structure 302 may be sinusoidal, sawtooth, rectangular or other shapes. The depth d of the micro-relief structure 302 can meet the following conditions, that is, when natural light (white light) illuminates the micro-relief structure 302 at an incident angle α, after the light beam passes through the micro-relief structure 302, light with a wavelength of λ (or a wavelength range) is reflected The light direction interferes constructively, so that the optical security element 3 observes the first color in the reflected light direction. In addition, if the light beam is in the Yoz plane (or a plane parallel to the Yoz plane), the optical security element 3 presents a second color in the direction of the scattered light in the Yoz plane (or a plane parallel to the Yoz plane); if the light beam is in the xoz plane ( Or a plane parallel to the xoz plane), the optical anti-counterfeiting element 3 observes the color of the +1 or -1 order diffracted light of the grating in the diffracted light direction and changes with the observation angle.

The depth d of the micro-relief structure 302 is generally between 100 nm and 5 μm, preferably 200 nm to 3 μm. The method for determining the depth d is the same as that in the first embodiment, and will not be repeated here. In addition, other features and beneficial effects of the optical anti-counterfeiting element 3 are the same as those of the above-mentioned optical anti-counterfeiting element 1, and will not be repeated here.

Hereinafter, the manufacturing process of the optical anti-counterfeiting element 1 in the embodiment of FIG. 1 will be illustrated by using FIGS. 4a-f.

Step 1: As shown in Figure 4a, an optical original plate with a micro-relief structure 102 is produced by a laser etching process, and electroformed into a metal plate roll. On the lower surface of the base layer 1011, the micro embossing process on the metal plate roll The relief structure is replicated as the micro relief structure 1021, and the refractive index of the material forming the micro relief structure 1021 can be around 1.48.

Step 2: As shown in FIG. 4b, a plating layer 104 is vapor-deposited on the surface of the micro-relief structure 1021, and the plating layer may be a 40 nm thick metal aluminum film reflective layer.

Step 3: As shown in FIG. 4c, a protective layer 105 is coated on the surface of the plating layer 104 in the area B by printing. The protective layer 105 may be an acrylic material, and its refractive index may be around 1.48.

Step 4: As shown in Figure 4d, immerse the structure shown in Figure 4c in a solution that can dissolve the plating layer 104 but cannot dissolve the protective layer 105. For example, the solution may be sodium hydroxide with a concentration of about 10% at 40°C. Aqueous solution until the reflective layer (for example, the reflective layer of a metal aluminum thin film) in the area A not covered by the protective layer 105 is completely reacted and dissolved, so that the plating layer 104 forms a hollow pattern.

Step 5: As shown in Figure 4e, the color functional layer 103 is vapor-deposited on the upper surface of the base layer 101, for example, an interference type multilayer film, that is, Al (thickness 40nm)/SiO ₂ (thickness 370nm)/ Cr (with a thickness of 5 nm), where the aluminum layer is in contact with the base layer 101. The interference type multilayer film of this parameter has the characteristics of being golden yellow when viewed from the front and green when viewed obliquely.

Step 6: As shown in Figure 4f, the structures shown in Figure 4d and Figure 4e are bonded together with a composite adhesive with adhesive properties. The refractive index of the composite adhesive is about 1.48, which is the same as 1021 and 105. The optical performance is the same, so the composite glue and 1021 and 105 are unified as 102 in FIG. 4f.

The above is a preferred typical implementation method for manufacturing the optical anti-counterfeiting element 1 described in FIG. 1. The production process of the optical

anti-counterfeiting elements

2 and 3 is similar to this, and will not be repeated here.

In the following, the shortcomings of the optical anti-counterfeiting element 1 will be explained in conjunction with FIGS. 4a to 4f and 5a to 5c.

Figure 5a corresponds to the top view image of the micro-relief structure 1021 with the plating layer 104 shown in Figure 4b on the xoy plane or a plane parallel to it, where different areas C and D are filled with different parameters (for example, the micro-relief structure in the plane Arrangement, structure depth, morphology and other parameters) micro-relief structure. In practical applications, regions C and D can also be further divided into macroscopic or microscopic sub-regions according to design requirements to fill micro-relief structures with different parameters.

Figure 5b corresponds to the micro-relief structure 1021 with the protective layer 105 applied in Figure 4c. Since the protective layer 105 and the micro-relief structure 1021 are processed in separate steps, the projection of the two on the xoy plane will appear objectively The inevitable misalignment error, according to the existing processing technology level, the misalignment error is usually more than 0.1 mm. When the area covered by the protective layer 105 is to cover the area D of the micro-relief structure 1021 without error as the initial design goal, it actually covers the area B. As a result, the uncertainty of the reserved area of the plating layer 104 is caused, which further causes the uncertainty of the position of the area A and the area B in the optical anti-counterfeiting element 1. For example, the image distortion and incompleteness shown in Fig. 5c inevitably appear in practical applications.

Figures 6a-b show an optimized embodiment for the image distortion and incomplete problems exposed in the embodiment of Figures 5a-c. Figure 6a shows a top view image of the micro-relief structure 1021 with the plating layer 104 on the xoy plane or a plane parallel to it, in which different areas C and D are filled with different parameters (such as the arrangement of the micro-relief structure in the plane, structure Depth, topography, etc.) micro-relief structure.

Fig. 6b corresponds to the micro-relief structure 1021 to which the protective layer 105 is applied shown in Fig. 4c. In order to avoid image distortion and defects, the coverage area of the protective layer 105 is slightly larger than the target coverage area D, and the excess size is, for example, at least 0.1 mm to ensure that the misalignment error is included. Therefore, the target coverage area D can still be fully included in the actual coverage area B even in the presence of the misalignment error, thereby ensuring the integrity of the image. However, this optimized structure brings another problem, that is, the plating layer 104 protected by the protective layer 105 covers the area outside the design target area D, that is, a part of the area C, which solves the image integrity and causes image redundancy. More. Moreover, the redundant plating layer 104 will affect the area and integrity of the region A where the color functional layer 103 is located.

In addition, neither the optical anti-counterfeiting element 1 described in FIG. 5 nor FIG. 6 can achieve a high-definition hollow pattern of the plating layer 104. This is limited by the printing process of the protective layer 105, and the line fineness in the existing printing process cannot exceed the stroke width of 0.01 mm.

In order to solve the problems described in Figure 5 and Figure 6, to ensure that the optical anti-counterfeiting element has higher uniqueness and easy identification and difficult to forge attributes. The present invention further provides another optical anti-counterfeiting element, which is described below with reference to FIG. 7.

7 is a schematic cross-sectional view of an anti-counterfeiting element 7 according to an embodiment of the present invention. The optical anti-counterfeiting element 7 includes a base layer 701, a color functional layer 703 located on the base layer 701, and an area B located on the color functional layer 703 and covering the color functional layer 703 At least a part of the micro-relief structure 702, the micro-relief structure 7022 of the area A covering the color functional layer 703, the area A and the area B do not overlap, and only the plating layer 704 covering the micro-relief structure 702. The ratio of the surface area to the apparent area of the micro-relief structure layer 702 is smaller than the ratio of the surface area to the apparent area of the micro-relief structure 7022. That is, the area covered by the plating layer 704 is determined by the difference in the ratio of the surface area to the apparent area of the micro-relief structure 702 and the micro-relief structure 7022.

Specifically, the micro-relief structure 702 and the micro-relief structure 7022 are composed of surface undulation structures whose height on the xoy plane fluctuates with the position distribution. Compared with a flat surface, the surface undulation structure is more than a flat surface. The surface area is larger, and the surface area is positively correlated with the degree of undulation of the surface undulating structure. In this article, the term "apparent area" refers to the area of the orthographic projection of a certain area in a plane parallel to the area, that is, the area ignoring the undulating structure in the area; the term "surface area" refers to the area State the actual area of the undulating structure in a certain area. Obviously, the ratio of the surface area of the certain area to its apparent area is a value not less than 1.

Preferably, the surface microstructure 7022 can be selected within the following range: one or more continuous curved structures, one or more rectangular structures, one or more sawtooth prisms, or their splicing or combination. Wherein, the continuous curved structure may be a splicing or combination of one or more structures of a micro lens structure, a sinusoidal structure, an elliptical structure, a hyperboloid structure, a parabolic structure, and the like. The microlens structure may be a refractive microlens, a diffractive microlens, or a splicing or combination thereof, wherein the refractive microlens may include a spherical microlens, an ellipsoidal microlens, a cylindrical microlens or other arbitrary geometric shapes based on Geometrical optics microlenses, diffractive microlenses include harmonic diffractive microlenses, plane diffractive microlenses, Fresnel zone plates, etc. In addition, the specific arrangement of the above structures may be periodic, partially periodic, aperiodic, random, or a combination thereof.

In the embodiment of FIG. 7, the feature size of the micro-relief structure 702 in the x-axis and y-axis directions is 2.8 μm, the refractive index of the material of the micro-relief structure 702 is n=1.48, the cross-sectional shape of the micro-relief structure 702 is sinusoidal, and the external medium For air, d=500nm. The micro-relief structure 7022 is a sinusoidal grating with an arrangement period of 350 nm and a depth of 300 nm. The processing process of the optical security element 7 is as follows:

Step 1: Use the laser etching process to make an optical original plate containing the micro-relief structure 702 and the micro-relief structure 7022, and electroform it into a metal plate roller, and copy the micro-relief structure on the metal plate roller using a molding process on the lower surface of a base layer For the micro-relief structure 702 and the micro-relief structure 7022, the refractive index of the material forming the micro-relief structure may be around 1.48.

Step 2: Evaporate a plating layer 704 on the surface of the micro-relief structure 702, and the plating layer may be a 50 nm thick metal aluminum film reflective layer.

Step 3: Immerse the structure formed in Step 2 in a solution capable of dissolving the plating layer 704. For example, the solution may be an aqueous solution of sodium hydroxide with a concentration of about 5% at 40°C. The plating layer on the surface of the micro-relief structure 7022 (for example, The metal aluminum film (reflective layer) is not dissolved until the coating layer 704 accurately covers the micro-relief structure 702, thereby forming a precise hollow pattern.

Step 4: Vapor-deposit the color functional layer 703 on the upper surface of the other base layer 701, for example, an interference type multilayer film, that is, sequentially vapor-deposit Al (thickness of 40nm)/SiO ₂ (thickness of 370nm)/Cr (thickness of 5nm), where the aluminum layer is in contact with the base layer 701.

Step 5: Use a composite adhesive with adhesive properties to bond the structures respectively formed in steps 3 and 4 together. The refractive index of the composite adhesive is about 1.48, which is consistent with the optical properties of the

micro-relief structures

702 and 7022.

The above are the implementation steps for manufacturing the optical anti-counterfeiting element 7 described in FIG. 7. Among them, the optical anti-counterfeiting feature of the part where area A is located is determined by the micro-relief structure 7022 and the color functional layer 703. However, the composite adhesive used in the processing has the same refractive index as the micro-relief structure 7022, so that the micro-relief structure 7022 does not contribute to The optical anti-counterfeiting feature of the area A, that is, the optical anti-counterfeiting feature of the part where the area A is located, is determined by the color functional layer 703. At the same time, the optical anti-counterfeiting feature of the part where the area B is located is determined by the micro-relief structure 702 and the coating 704 on the surface thereof.

Taking the color functional layer 703 as an interference-type multilayer film, and the plating layer 704 as a metal aluminum thin-film reflective layer as an example, the area A in Figure 7 can provide the interference-type multilayer film with a golden-yellow-to-green feature, and the area B can be Provides features that appear yellow in the direction of reflected light and blue in the direction of scattered light. That is, when viewed in the direction of the reflected light, the area where the area A is located and the area where the area B is located are golden yellow and yellow respectively, and the two areas change to green and blue respectively as the viewing angle continues to be tilted. The other features and beneficial effects of the optical anti-counterfeiting element 7 are the same as those of the above-mentioned optical anti-counterfeiting element 1, which will not be repeated here.

8 is a schematic cross-sectional view of an anti-counterfeiting element 8 according to another embodiment of the present invention. The optical anti-counterfeiting element 8 includes a base layer 801, a color functional layer 803 located on the base layer 801, and a color functional layer 803 covering the color functional layer 803. At least a part of the micro-relief structure 802 of the area B, the micro-relief structure 8022 of the area A covering the color functional layer 803, the area A and the area B do not overlap, and only the plating layer 804 covering the micro-relief structure 802. The undulation height of the micro-relief structure layer 802 is smaller than the undulation height of the micro-relief structure 8022. That is, the area covered by the plating layer 804 is determined by the difference in height of the undulations of the micro-relief structure 802 and the micro-relief structure 8022.

Preferably, the surface microstructure 8022 can be selected within the following range: one or more continuous curved structures, one or more rectangular structures, one or more sawtooth prisms, or their splicing or combination. Wherein, the continuous curved structure may be a splicing or combination of one or more structures of a micro lens structure, a sinusoidal structure, an elliptical structure, a hyperboloid structure, a parabolic structure, and the like. The microlens structure may be a refractive microlens, a diffractive microlens, or a splicing or combination thereof, wherein the refractive microlens may include a spherical microlens, an ellipsoidal microlens, a cylindrical microlens or other arbitrary geometric shapes based on Geometrical optics microlenses, diffractive microlenses include harmonic diffractive microlenses, plane diffractive microlenses, Fresnel zone plates, etc. In addition, the specific arrangement of the above structures may be periodic, partially periodic, aperiodic, random, or a combination thereof.

In the embodiment of FIG. 8, the characteristic size of the micro-relief structure 802 in the x-axis and y-axis directions is 4.0 μm, the refractive index of the material of the micro-relief structure 802 is n=1.48, the cross-sectional shape of the micro-relief structure 802 is rectangular, and the external medium is Air, d=600nm. The micro-relief structure 8022 is a one-dimensional arrangement of cylindrical mirrors, the arrangement period of which is 20 μm, the distance between the bottoms of adjacent cylindrical mirrors is 1.5 μm, and the height of the cylindrical mirrors is 3.5 μm. The processing process of the optical security element 8 is as follows:

Step 1: Use a laser etching process to make an optical original plate containing a micro-relief structure 802 and a micro-relief structure 8022, and electroform it into a metal plate roll, and copy the micro-relief structure on the metal plate roll using a molding process on the lower surface of a base layer For the micro-relief structure 802 and the micro-relief structure 8022, the refractive index of the material forming the micro-relief structure is around 1.48.

Step 2: A plating layer 804 is vapor-deposited on the surface of the micro-relief structure 802, and the plating layer may be a metal aluminum thin film reflective layer with a thickness of 50 nm.

Step 3: Coating a protective layer on the entire surface of the plating layer 804. The protective layer is preferably a polymer, especially a polymer containing cellulose. For example, the polymer forming the protective layer may include a mixture of nitrocellulose (preferably nitro alcohol) and a resin (such as gum arabic and rosin) added to improve the resistance to subsequent processing of the protective layer. In a preferred embodiment, the main resin is a polyester resin material, the resin material contains the following components: (1) about 20 wt% to about 30 wt% of the main resin, the resin is a polyester with a hydroxyl value greater than 120 , The polyester is a branched hydroxy polyester with a viscosity of 25000±5000mPa.s; (2) about 10wt% to about 25wt% of nitrocellulose, the nitrocellulose has a nitrogen content of <12.4% (3) about 5wt% to about 25wt% of a crosslinking agent, the crosslinking agent is an isocyanate oligomer; and (4) about 20wt% to about 60wt% of a solvent. The refractive index of the protective layer is around 1.48.

Step 4: Immerse the structure formed in Step 3 into a solution that can dissolve the plating layer 804 but not the protective layer. The solution can be an aqueous solution of sodium hydroxide with a concentration of about 10% at 40°C. The plating layer on the surface of the micro-relief structure 8022 ( For example, the metal aluminum film reflective layer) is not dissolved until the reaction is completed, so that the plating layer 804 accurately covers the micro-relief structure 802, thereby forming a precise hollow pattern. The specific reaction process is as follows: the protective layer does not completely cover the plating layer 804 on the micro-relief structure 8022, so the environment is reacted with the exposed plating layer 804 on the micro-relief structure 8022 to achieve hollowing of the area. At the same time, the next stage of the reaction process is that the environment is centered on the exposed plating layer 804 in the micro-relief structure 8022 and penetrates into the plating layer 804 covered by the protective layers on both sides, thereby further interacting with the micro-relief structure 8022. The plating layer 804 covered by the protective layer reacts to be translucent, and even becomes fully transparent as the reaction process continues. During the entire reaction process, the plating layer 804 on the micro-relief structure 802 is completely covered by the protective layer, so that it does not participate in the reaction and is retained.

Step 5: Vapor-deposit the color functional layer 803 on the upper surface of the base layer 801, for example, an interference type multilayer film, that is, sequentially vapor-deposit Al (thickness of 40nm)/SiO ₂ (thickness of 270nm)/Cr (thickness of 5nm) , Where the aluminum layer is in contact with the base layer 801.

Step 6: Use a composite adhesive with adhesive properties to bond the structures formed in steps 4 and 5 together. The refractive index of the composite adhesive is about 1.48, which is compatible with the protective layer and micro-relief structures 802 and 8022. The optical performance is consistent.

The above are the implementation steps for manufacturing the optical anti-counterfeiting element 8 described in FIG. 8. Among them, the optical anti-counterfeiting feature of the part where the area A is located is determined by the micro-relief structure 8022 and the color functional layer 803. However, the composite glue, the protective layer and the micro-relief structure 8022 used in the processing have the same refractive index, making the micro-relief structure 8022 It does not contribute to the optical anti-counterfeiting feature of the portion where the area A is located, that is, the optical anti-counterfeiting feature of the portion where the area A is located is determined by the color functional layer 803. At the same time, the optical anti-counterfeiting feature of the part where the area B is located is determined by the micro-relief structure 802 and the coating 804 on the surface thereof.

Taking the color functional layer 803 as an interference-type multilayer film, and the plating layer 804 as a metal aluminum film reflective layer as an example, the area A in Figure 8 can provide the red-to-green feature of the interference-type multilayer film, and the area B can provide It appears green in the direction of reflected light and magenta in the direction of scattered light. That is, when viewed in the direction of the reflected light, the area where the area A is located and the area where the area B is located respectively appear red and green, and the two areas change to green and magenta respectively as the viewing angle continues to be tilted. The other features and beneficial effects of the optical anti-counterfeiting element 8 are the same as those of the above-mentioned optical anti-counterfeiting element 1, and will not be repeated here.

The anti-counterfeiting element of the present invention can integrate a variety of other types of relief structures, such as ordinary diffractive optically variable images, blazed grating structures, and the like. For example, in area B in FIG. 1a, while the micro-relief structure 102 exists, a rainbow or achromatic holographic image is added. The holographic image may adopt a sinusoidal, rectangular, and/or sawtooth microstructure, which has diffraction or non The diffractive optical feature, thereby providing a color feature or image feature that is different from the micro-relief structure 102 that does not have to satisfy the interference constructive condition. The holographic image can be formed on the original plate synchronously with the micro-relief structure 102 to reduce the complexity of the process, or be generated step by step in the subsequent processing, for example, by using two molding methods.

The anti-counterfeiting element of the present invention can also be hot stamping type, that is, a release layer is coated on the substrate, and then the anti-counterfeiting element of the present invention is fabricated on the release layer. After the hot stamping process is applied to transfer it to the carrier, the substrate Peel it off.

The anti-counterfeiting element of the present invention further has other functional layers, such as a magnetic information layer, a fluorescent anti-counterfeiting feature layer, a printed pattern layer, an adhesive layer and the like.

The anti-counterfeiting element of the present invention can be applied to transfer or stick to a carrying object in the form of identification, hot stamping of wide strips, stickers, security threads, etc. These carrying objects can be high-security products such as banknotes, securities, credit cards, and passports, or high-value-added products.

Correspondingly, an embodiment of the present invention also provides an optical anti-counterfeiting product, including the above-mentioned optical anti-counterfeiting element.

The above described alternative implementations of the embodiments of the present invention in detail with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the foregoing embodiments. Within the scope of the technical concept of the embodiments of the present invention, the embodiments of the present invention can be compared. The technical solution of the invention undergoes many simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

In addition, it should be noted that the various specific technical features described in the foregoing specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, various possible combinations are not further described in the embodiment of the present invention.

In addition, various different implementations of the embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the embodiments of the present invention, they should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

An optical anti-counterfeiting element, which includes:

Grassroots

A color functional layer located on the base layer;

A first micro-relief structure covering at least a part of a first area of the color functional layer, the first area being a partial area of the color functional layer; and

Only the plating layer covering the surface of the first micro-relief structure;

The first micro-relief structure is defined as when a light beam illuminates the first micro-relief structure at an incident angle, light of a wavelength or wavelength range in the light beam interferes constructively in the direction of the reflected light.
The optical security element of claim 1, wherein the optical security element further comprises:

A second micro-relief structure covering a second area of the color functional layer excluding the first area, and the ratio of the surface area of the first micro-relief structure to the apparent area is smaller than that of the second micro-relief The ratio of the surface area of the structure to the apparent area.
The optical security element of claim 1, wherein the optical security element further comprises:

For the second micro-relief structure covering the second area of the color functional layer except the first area, the undulation height of the first micro-relief structure is smaller than the undulation height of the second micro-relief structure.
The optical anti-counterfeiting element according to any one of claims 1 to 3, wherein the depth of at least a part of the first micro-relief structure satisfies the following conditions:

When the light beam irradiates at least a part of the first micro-relief structure at an incident angle, after the light beam passes through at least a part of the micro-relief structure, light of a wavelength or wavelength range in the light beam interferes in the direction of the reflected light. Long, so that at least a part of the optical anti-counterfeiting element presents the first color in the direction of the reflected light.
The optical anti-counterfeiting element according to claim 4, wherein the pattern of at least a part of the first micro-relief structure is at least one or any combination of the following:

The relief units of the first micro-relief structure are randomly or pseudo-randomly distributed;

The relief units of the first micro-relief structure are randomly or pseudo-randomly distributed in one direction; and

The relief units of the first micro-relief structure are periodically distributed in the first direction, and randomly or pseudo-randomly distributed in the second direction.
The optical anti-counterfeiting element according to claim 5, wherein, when the pattern of at least a part of the first micro-relief structure is randomly or pseudo-randomly distributed, the relief units of at least a part of the first micro-relief structure The characteristic size of at least a part of the first micro-relief structure is 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the depth of at least a part of the micro-relief structure also satisfies the following conditions:

When the light beam irradiates at least a part of the first micro-relief structure at an incident angle, at least a part of the optical anti-counterfeiting element presents a second color in the direction of scattered light.
The optical anti-counterfeiting element according to claim 5, wherein the pattern on at least a part of the first micro-relief structure is that the relief units of at least a part of the first micro-relief structure are randomly or pseudo-randomly distributed in the second direction In this case, at least a part of the first micro-relief structure has a characteristic size in the second direction of 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the characteristic size in the first direction is greater than 6 μm, preferably greater than 10 μm, and the first The depth of at least a part of the micro-relief structure also meets the following conditions:

When the light beam irradiates at least a part of the first micro-relief structure at an incident angle, if the light beam is in a first plane perpendicular to the plane of the base layer and including the second direction, the optical At least a part of the anti-counterfeiting element presents a second color in the direction of scattered light in the first plane.
The optical anti-counterfeiting element according to claim 5, wherein the pattern on at least a part of the first micro-relief structure is at least a part of the first micro-relief structure. The relief units are periodically distributed in the first direction, and in the second In the case of random or pseudo-random distribution, the characteristic size of at least a part of the first micro-relief structure in the first direction is 0.3 μm-6 μm, preferably 0.6 μm-3 μm, and the characteristic size in the second direction is 0.3 μm-6μm, preferably 0.6μm-3μm, the depth of at least a part of the micro-relief structure also meets the following conditions:

When the light beam irradiates at least a part of the first micro-relief structure at an incident angle, if the light beam is in a first plane perpendicular to the plane where the base layer is located and includes the second direction, the optical At least a part of the anti-counterfeiting element presents a second color in the direction of scattered light in the first plane; if the light beam is in a second plane perpendicular to the plane where the base layer is located and containing the first direction, the optical anti-counterfeiting At least a part of the element presents the color of diffracted light of +1 order or -1 order in the direction of diffracted light in the second plane.
The optical anti-counterfeiting element according to any one of claims 1 to 3, wherein the color functional layer is one or a combination of ink, pigment, and dye.
The optical anti-counterfeiting element according to any one of claims 1 to 3, wherein the color functional layer is a liquid crystal light variable layer.
The optical anti-counterfeiting element according to any one of claims 1 to 3, wherein the color functional layer is a multi-layer co-extruded optically variable film.
The optical anti-counterfeiting element according to any one of claims 1 to 3, wherein the color functional layer is an interference type multilayer film structure, and the interference type multilayer film structure forms a Fabry-Perot cavity .
The optical anti-counterfeiting element according to claim 1, wherein the plating layer is a metal reflective layer.
The optical anti-counterfeiting element according to claim 1, wherein the cross-section of the relief unit of the first micro-relief structure is any one of the following: sinusoidal, zigzag, or rectangular.
The optical security element of claim 1, wherein the optical security element further comprises:

A holographic image covering the other part of the first area except the first micro-relief structure.
An optical anti-counterfeiting product comprising the optical anti-counterfeiting element according to any one of claims 1 to 15.